Classifications

• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
  • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
  • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V5/00—Refractors for light sources
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0033—Means for improving the coupling-out of light from the light guide
  • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0033—Means for improving the coupling-out of light from the light guide
  • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
  • G02B6/0051—Diffusing sheet or layer
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/133553—Reflecting elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/1336—Illuminating devices
  • G02F1/133616—Front illuminating devices
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S977/00—Nanotechnology
  • Y10S977/70—Nanostructure
  • Y10S977/832—Nanostructure having specified property, e.g. lattice-constant, thermal expansion coefficient
  • Y10S977/834—Optical properties of nanomaterial, e.g. specified transparency, opacity, or index of refraction

Definitions

• This application relates generally to illuminated display devices, particularly display devices that are front-lit with an illumination device.
• this application describes a front-lit reflective display assembly including a reflective display and an illumination article.
• the illumination article includes a lightguide and a variable index light extraction layer, where the variable index light extraction layer is optically coupled to the lightguide and the reflective display.
• the variable index light extraction layer has first and second regions, where the first region includes nanovoided polymeric material, and the second region includes the nanovoided polymeric material and an additional material.
• the first and second regions are disposed such that for light emitted by a light source and injected into the lightguide, the variable index light extraction layer selectively extracts the light in a predetermined way based on the geometric arrangement of the first and second regions.
• this application describes a front-lit reflective display device including the front-lit reflective display assembly optically coupled to a light source.
• FIGS. 4c and 4d show profiles for selected optical properties % transmission and % clarity, respectively, for the variable light extraction layer shown in FIG. 4a.
• FIG. 6 shows a schematic of an exemplary illumination device comprising the variable index light extraction layer in combination with a light source and a reflective scattering element.
• FIG. 7 shows a schematic of an exemplary illumination assembly comprising the variable light extraction layer in combination with a reflective scattering element.
• FIG. 12 shows a schematic cross-sectional view of an exemplary optical film comprising the variable index light extraction layer.
• FIGS. 16a and 16b show reflective display devices with a front light having the variable index extraction layer, wherein the light is off and on, respectively.
• variable index light extraction layer allows the lightguide to be transparent exhibiting little to no haze and high clarity with and without illumination. This allows for viewing of images on a reflective display or of a graphic without significant reduction in resolution and contrast, and without visible optical artifacts generated by light scattered or diffracted by different regions.
• extraction layers have light scattering features in order for light being transported within the lightguide by TIR (at angles equal to or greater than the critical angles) in a lightguide to be directed out of the lightguide. These light scattering features typically comprise diffuse reflective printed extraction dots or structures that are disposed on or are etched into the surface of the lightguide which cause significant reduction in the viewing quality when looking through the lightguide.
• FIG. lb shows a schematic cross section of an exemplary variable index light extraction layer disposed on a transparent adjacent layer.
• Optical film 105 comprises variable index light extraction layer 100 disposed on adjacent layer 120 which is a transparent substrate.
• Variable index light extraction layer 100 comprises first regions 140a and 140b, and second region 130 disposed between the first regions.
• the second region comprises the nanovoided polymeric material and an additional material, and has a second refractive index that is different from the first refractive index by at least about 0.03.
• the nanovoided polymeric material is the same material in both the first and second regions.
• a material is considered an additional material if it is incorporated substantially within the variable index light extraction layer and causes a change in refractive index of the first region by at least about 0.03, for example, from about 0.03 to about 0.5, from about 0.05 to about 0.5, or from about 0.05 to about 0.25.
• the first region of the variable light extraction layer has an effective index of refraction and includes a plurality of nanovoids if the size of at least a majority of the nanovoids, such as at least 60% or 70% or 80% or 90% of the nanovoids, is not greater than about 70 nm, or not greater than about 60 nm, or not greater than about 50 nm, or not greater than about 40 nm, or not greater than about 30 nm, or not greater than about 20 nm, or not greater than about 10 nm.
• aromatic constituents of oligomers and/or polymers generally tend to have poor weatherability and/or poor resistance to sunlight, aromatic constituents can be limited to less than 5 weight percent, preferably less than 1 weight percent, and can be substantially excluded from the oligomers and/or polymers and the reactive diluents of the present disclosure. Accordingly, straight- chained, branched and/or cyclic aliphatic and/or heterocyclic ingredients are preferred for forming oligomers and/or polymers to be used in outdoor applications.
• the particles can have a regular shape such as spherical, or an irregular shape.
• the particles can be elongated having an average aspect ratio that is not less than about 1.5, not less than about 2, not less than about 3, not less than about 4, or not less than about 5.
• the particles can be in the form or shape of a string- of-pearls (such as SNOWTEX-PS particles available from Nissan Chemical) or aggregated chains of spherical or amorphous particles, such as fumed silica.
• the additional material is incorporated into the nanovoided polymeric material with little or no additional material on a surface of the nanovoided polymeric material.
• the additional material substantially completely fills the interconnected nanovoids such that little or no void volume (less than 5% void volume) remains within the second region.
• the additional material partially fills the interconnected nanovoids such that some void volume remains.
• the second regions comprise a particular amount of void volume depending upon the refractive index of the additional material and the desired difference in refractive indices between the first and second regions.
• the second region may have a void volume less than about 20%, less than about 10%, less than about 5% or less than about 1%.
• Second regions 420 are shaped as rectangles or stripes of substantially the same length and width, extending across the width of layer 400, and disposed from left to right with increasing frequency.
• Second regions 420 have a refractive index greater than that of first region 410 by at least about 0.03.
• FIG. 4b illustrates the refractive index profile for variable index light extraction layer 400 with the x-axis identifying positions d down the length of the layer at some substantially single position wj as shown in FIG. 4a.
• the refractive index profile shows the variation in the refractive index of layer 400 which comprises a pattern between first and second refractive indices, « / and n 2 , respectively.
• FIGS. 4c and 4d show profiles for selected optical properties % transmission and % clarity, respectively, and for both properties, there is substantially little or no variation down the length of the layer.
• the viscoelastic lightguide comprises a PSA layer as described in the Dalquist criterion line (as described in Handbook of Pressure Sensitive Adhesive Technology, Second Ed., D. Satas, ed., Van Nostrand Reinhold, New York, 1989.)
• the stretch releasable PSA may comprise an MQ tackifying resin and an elastomeric silicone polymer selected from the group consisting of urea-based silicone copolymers, oxamide-based silicone copolymers, amide-based silicone copolymers, urethane -based silicone copolymers, and mixtures thereof.
• Suitable seal layers include pressure sensitive adhesive polymers and copolymers which can be acrylic or acrylate based, styrene butadiene, or styrene isoprene type copolymer thermoplastic resins and similar polymers so long as they do not contain a significant fraction of low molecular weight species capable of penetration into the nanovoided first region.
• passive optical components having small emitting areas such as lenses, deflectors, narrow light guides, and the like that give off light received from an active component such as a bulb or LED die.
• a passive component is a molded encapsulant or lens of a side-emitting packaged LED. Any suitable side-emitting LED can be used for one or more light sources, e.g., LuxeonTM LEDs (available from Lumileds, San Jose, CA), or the LEDs described, e.g., in US 7,525, 126 (Leatherdale et al.) and US 2007/0257270 (Lu et al.).
• Printing may also comprise other processes including but not limited to rotogravure printing, screen printing, inkjet printing (aqueous, solvent or solid-based inks may be used), letterpress printing, offset printing, heat transfer methods using heat sensitive substrates, thermal dye transfer and dye sublimation printing, dot-matrix printing, and printing with daisy wheels.
• the reflective scattering element can take the form of inks, paint, or coatings.
• Printed graphics made by such methods as digital printing, silk screen, etc. are reflective scattering elements.
• a painted wall is a reflective scattering element.
• the reflective scattering element comprises a reflective display device.
• FIG. 7 shows a schematic of an exemplary illumination assembly comprising the variable light extraction layer in combination with a reflective scattering element.
• variable index light extraction layer 730 is made on transparent substrate 740 which is incorporated into the illumination assembly.
• Surface 725 of variable index light extraction layer 730 is optically coupled to lightguide 710, and bottom side 742 of transparent substrate 740 is optically coupled to reflective scattering element 750.
• Suitable transparent substrates are described above.
• FIG. 12 shows a schematic cross-sectional view of an exemplary optical film comprising the variable index light extraction layer.
• Optical film 1200 comprises variable index light extraction layer 1230 disposed on transparent substrate 1240.
• First optically clear adhesive layer 1270 is disposed on variable index light extraction layer 1230 opposite the transparent substrate, and first release liner 1275 is disposed on layer 1270 opposite layer 1230.
• Second optically clear adhesive layer 1260 is disposed on transparent substrate 1240 opposite variable index light extraction layer 1230, and second release liner
• This optical film 1200 can be used in conjunction with a light guide and a reflective scattering element layer to make illumination devices for applications in general illumination (for example task lighting, room lighting, under cabinet lighting, and automotive interior lighting) or for backlighting applications (for example backlighting of liquid crystal displays suitable for mobile handheld, computer monitor and notebook, and TV and digital signage applications, backlighting of any other transparent display types that are transmissive and graphics made by any means, for example graphics made by printing methods), or can be used as a front light with reflective display devices and graphics to make front illuminated reflective display devices or graphics.
• general illumination for example task lighting, room lighting, under cabinet lighting, and automotive interior lighting
• backlighting applications for example backlighting of liquid crystal displays suitable for mobile handheld, computer monitor and notebook, and TV and digital signage applications, backlighting of any other transparent display types that are transmissive and graphics made by any means, for example graphics made by printing methods
• backlighting applications for example backlighting of any other transparent display types that are transmissive and graphics made by any means, for example graphics made by printing methods
• the reflective display may comprise an electrofluidic display.
• an electrofluidic display is an electrowetting display, a relatively new technology, originally described in "Video- Speed Electronic Paper Based on Electrowetting" by R.A. Hayes and B.J.Feenstra in Nature, Vol. 425, 383-385 (25 September 2003) and developed by Liquavista BV.
• Electrowetting displays comprise a transparent electrode, hydrophobic insulator, a colored oil layer and water, sandwiched between glass or polymeric substrates. In equilibrium the colored oil naturally forms a stable continuous film between the water and the hydrophobic insulator.
• the system When a voltage difference is applied across the hydrophobic insulator, the system lowers its energy by moving the water into contact with the insulator, thereby displacing the oil and exposing the underlying reflecting surface.
• the balance between electrostatic and surface tension forces determines how far the oil is moved to the side. In this way the optical properties of the stack when viewed from above can be continuously tuned between a colored off-state and a transparent on- state, provided the pixel is sufficiently small so that the eye averages the optical response.
• electrofluidic displays made using "Young-N"
• the top surfaces of the reflective displays are optically coupled to the reflective surface in the reflective display element of the display device in the sense that there are no air gaps between the top surface and the reflective display element of the display device.
• the refractive index of the top surface and other layers of the reflective display device above the reflective element of the display have a refractive index that is greater than the nanovoided polymeric first region of the variable index light extraction layer. In some cases the refractive index of the layers in the display device that are between the reflective surface or element of the display are equal to or higher than the index of the lightguide of the illumination article 1301.
• the above coating formulation was coated onto 50 um PET film (MELINEX 617 available from DuPont) using a slot die at a line speed of 3.1 ml min.
• the wet coating thickness was approximately 14 um.
• the wet coating was partially cured in-line at the same line speed with UV radiation at 395 nm and dose of 850 mJ/cm 2 (UV radiation was provided by UV-LEDs available from Cree, Inc.).
• the partially cured coating sample was then dried at 70°C in a 9 meter oven, and under a nitrogen-purged atmosphere, finally cured with a 236 Watt/cm 2 Fusion H bulb (available from Fusion UV Systems, Inc.).
• the nanovoided polymeric layer was printed with a UV curable clear ink (UV OP 1005 GP).
• FIG. 16b shows an image of the front lit device and a plot of the axial luminance as a function of position.
• the display uniformity is greater than 75% as measured using the formula ((max -min)/max x 100%).
• a front-lit reflective display device was assembled as described above for Example 2 with the exception that the variable index light extraction layer on PET support was not included.
• the PSA lightguide was adhered to the viewing panel of the electronic book using the self-wetting adhesive.
• the self-wetting adhesive was used in order to facilitate rework of the assembly when the lightguide was removed from the electronic book at a later time).
• the luminance uniformity was measured on the illuminated device using a Prometric camera (available from Radiant Imaging, Redmond, WA).
• FIG. 17b shows an image of the front lit device and a plot of the axial luminance as a function of position. It is immediately apparent that the display uniformity is poor.
• the luminance uniformity is less than 5% as measured using the formula ((max -min)/max x 100%).
• the resulting batch was a translucent, low- viscosity dispersion.

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• Materials Engineering (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
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• 2012
  • 2012-02-23 CN CN201280008599.2A patent/CN103354917B/zh not_active Expired - Fee Related
  • 2012-02-23 US US13/984,239 patent/US10288254B2/en not_active Expired - Fee Related
  • 2012-02-23 WO PCT/US2012/026237 patent/WO2012116129A1/en active Application Filing
  • 2012-02-23 KR KR1020137025026A patent/KR101877593B1/ko active IP Right Grant
  • 2012-02-23 EP EP12707215.5A patent/EP2678736B1/en not_active Not-in-force
  • 2012-02-24 TW TW101106332A patent/TWI548912B/zh active

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